SURBL
SURBL (Spam URI Real-time Block List) is a DNS-based blocklist used to help filter spam by identifying URLs contained within messages. Unlike traditional IP-based blocklists that target sending hosts, SURBL focuses on the domains that appear in the hyperlinks of emails, banners, or other URI-bearing content. It is commonly used as part of multi-layer spam filtering in mail servers and content scanners to reduce the spread of messages that rely on malicious or promotional URLs.
How SURBL works: The system maintains lists of domains that have appeared in spam URLs. When a
Lists and usage: SURBL provides several lists, including a multi-list aggregator that collects entries from multiple
Limitations and considerations: SURBL reflects domains that have appeared in spam, so legitimate sites may occasionally
See also: DNS-based blacklists, URI DNSBLs, spam filtering, email security.